Musical instrument



Feb, 9,1943. P. M- BARTH' 2,310,606

MUSICAL INSTRUMENT Filed oct. 25', 1941 \\\\\\\\\\\I|IIlllIlI/l/l/l Patented Feb. 9, 1943 UNITED STATES PATENT OFFICE MUSICAL INSTRUMENT Paul M. Barth, Manhattan Beach, Calif. Application October 25, 1941, Serial No. 416,532

9 Claims.

This invention relates to musical instruments and relates more particularly to stringed musical instruments embodying or capable of embodying electrical pickup means. A general object of this invention is to provide a practical, effective and inexpensive means for embodying electrical pickup units in stringed musical instruments.

Stringed musical instruments have been introduced which embody electrical pickups at the strings for converting the vibrations of the strings into induced electrical currents which in turn are reproduced as sound by an amplifying and sound reproducing circuit. So far as I am aware, the pickup units of these prior instruments have always been secured directly to lthe bodies of the instruments, press against or rest on the instrument bodies at or adjacent the strings. For eX- ample, in the case of an electrical guitar, the pickup unit is directly attached to the upper face of the instrument body. The attachment of the pickup to the vibratile upper board of the resonant instrument' body dampens or kills the resonance of the instrument 'and the instrument is practically useless unless the pickup is energized and is connected with the amplifying and sound reproducing means. Musicians often prefer to play the very line old instruments which may have' been in their possession for many years and, in most cases, will not permit the tonal qualities of these instruments to be destroyed by the attachment of the electrical pickups. For this reason, such musicians are obliged to purchase and employ instruments designed solely or primarily as electrical instruments and are not able to play their favorite or customary instruments. The usual electrical instrument is not operative unless its pickup is connected with the amplifying and sound producing unit and Where there is no available source of electricity such instruments canno-t be used.

Another object of this invention is to provide means for mounting or providing an electrical pickup on a stringed instrument such as a violin, guitarJ or the like, without in any Way affecting the resonance or tonal qualities of the instrument, thus allowing the instrument to be played either with or Without the benet of the pickup means. The present invention provides for the embodiment of an electrical pickup in an instrument 4of the violin and guitar class in such a vvay` that the natural tonal qualities of the instrument are unaffected and remain exactly as before the attachment of the pickup, permitting the musician to play the instrument Without utilizing the electrical pickup means and allowing him to employ the pickup means and the amplifying unit when an amplincation of the sound is desired.

Another object of this invention is to provide a musical instrument of the class embodying a resonant sound box or body and including an electrical pickup means so mounted and arranged that it does not dampen or in any Way alter the tonal qualities of the resonant body so that the instrument may be used or played either with or Without the pickup energized.

Another object of this invention is to provide a novel and effective means for applying or attaching an electrical pickup unit to a previously constructed musical instrument of the class embodying a resonant sound box or body Without dampening or in any Way affecting the resonance or tonal qualities of theinstrument.

Another object of this invention `is to provide means for mounting an electrical pickup on a previously constructed stringed musical instrument which is adjustable to suit it for instruments varying considerably in size and to compensate for any irregularities in the shapes or conngurations of the instruments.

Another object of this invention is to provide means of the character referred to for mounting an electrical pickup on a stringed musical instrument which permits adjustment of the pickup with respect to the strings to provide for the most eilicient operation of the pickup.

Another object of this invention is to provide means of the character referred to for mounting an electrical pickup o-n a stringed musical instrument Which is quickly applied to and easily detached from the instrument allowing the electrical pickup to be applied and removed at Will.

A further object of this invention is to provide a readily removable mounting means of the character referred to which does not necessitate the formation of openings in the instrument body, or require the provision of permanent screws, bolts, pins or other parts which may detract from the appearance of the instrument and which does not, in any way, may or injure the nish of the instrument.

The various Objects and features of my invention will be fully understood from the following detailed description of typical preferred forms and applications of my invention, throughout which description reference is made to lthe accompanying drawing, in which:

Fig. l is a face or plan view of a stringed musical instrument embodying the features of the present invention. Fig. 2 is a transverse detailed sectional View taken as indicated by line 2-2 on Fig. l showing the pickup and the mounting means in elevation. Fig. 3 is an enlarged vertical detailed sectional view illustrating the pickup and the adjacent portion of the mounting means with the pickup appearing in side elevation. Fig. 4 is an enlarged transverse detailed sectional View taken as indicated by line 4-4 on Fig. 3 and Fig. 5 is a fragmentary perspective View of a clamp means for removably or detachably securing the mounting means to the instrument body.

The present invention may be embodied in units or structures applicable to practically any instrument of the violin class, for example, it may be embodied in forms for use on violins, violas, bass viols, cellos, guitars, ukeleles, etc. The structure of the invention may be modified in size and construction to adapt it for application to the different instruments. In the following detailed disclosure I will describe the invention as employed in connection with a guitar, it bein-g understood that the inventionis not' to be construed as limited or restricted to the specic structure herein disclosed.

The instrument or guitar illustrated in the drawing comprises the usual vibratile and resonant body IB, the neck Il extending from the body l and the finger board I2 on the neck Il equipped with the usual. fretsV i3. Ferrous metal strings S extend from pegs i4 on the outer part.

of the neck ll to the usual tailpiece I5. The strings S bear on a bridge I6 supported by the top member l1 of the sound box or body I0. The

sound box l1), as illustrated in Fig; 2 of the drawing, includes the top member l1, a correspondingly shaped bottom member 18 and curved sides I9. In accordance with the usual practice, vstrengthening corner strips il occur on the interior of the sound box or body Il) where the sides I9 join the top and bottom members l1 and I8.A The elements of the instrument thus far described are typical or conventional.

The structure of the invention as illustrated in Figs. l to 4, inclusive, may be said to comprise, generally, a supporting bridge 20 extending across the top of the instrument body I0, an electrical pickup 2|, and means 22 for adjustably supporting the pickup 2l on the bridge 20.

The bridge 20 serves to mount or support the pickup 2l in its operative position at the vibratile strings S without dampening or deadening the resonant instrument body I0. The bridge 20 extends across the top member I1 of the instrument without contacting the member at any point except at its margins where and non-vibratile due to its connection with the instrument sides I9. While the bridge 20 may be of one-piece construction designed and proportioned to t a given instrument or an instrument of given size, make or type, it is preferred to make the bridge 20 adjustable or extensible and contractible to be useful on various instruments and to properly t instruments which vary in their configuration or which may be somewhat irregular.

In accordance with the invention the bridge 2i] is an elongate structure extending transversely across the top of the instrument body IB to pass under the strings S at a point spaced forwardly from the bridge I5. The extensible or adjustable bridge 2i) comprises two end sections 23 and an intermediate section 24 connected for relative longitudinal movement. The end sections 23 have flanges or feet 25 at their outer ends for resting on the top body member l1 at its side edges or the member l1 is firm margins. The feet 25 are broadened along the margins ci the body member l1 and are secured to the instrument body 18 by screws 2t. The screws 2; may pass through the relatively thin top member il' and screw into the reenforcing strip members 9. The end sections 23 bow or slope upwardly and inwardly from their feet 25 toward the strings S and are shaped to remain clear of and spaced from the top member I1 at all points except at their feet 25. The inner ends of the end sections 23 have flat generally horizontal parts 21. It is usually preferred to construct the members 23 of metal which is suitably plated or iinished and, for reasons to be later set forth, it is preferred to employ non-magnetic metal. Depending flanges 23 extend along the longitudinal edges of the end sections 23 to lend strength and rigidity to the sections. The flanges 23 extend from adjacent the feet 25 to the inner ends of the parts 21. The flanges 28 are spaced above the top member i1 at all points.

The intermediate bridge section 24 extends between and connects the end sections 23. The major portion of the intermediate section 24 is straight and generally horizontal. The intermediate section 24 is provided with end parts 29 which are stepped down from the major flat part of the section and these end parts 23 have sliding or telescopic cooperation with the inner end parts 21 of the end sections 23. Depending strengthening ilanges 3i) extend along the longitudinal edges of the section 24 and these flanges 30 cooperate with the flanges 2S of the parts 21 to guide the sections and to hold the sections 23 and 24 against relative lateral movement and displacement. rfhe overlapping parts 21 and 29 of the sections 22 and 24 have registering longitudinal slots 2l. Bolts or screws 32 pass through the lslots 3l. Washers 33 are provided under the heads of the screws 32 to bear against the tops of the parts 2Q and nuts 34 are threaded on the lower ends ci the screws to clamp against the under sides of the parts 21. When the screws 32 are loosened the bridge 2 may be lengthened or shortened in its entirety and the intermediate section 24 may oe shifted back and forth in either direction to centralize it relative to the strings S. When one screw 32 is loosened one end portion of the bridge 20 may be shortened or lengthened, that is, one end section 23 may be moved in or out to bring its foot 25 at the margin of the instrument body l0. These adjustments adapt the bridge 2i) for use on instruments whose strings S yare not truly central of the body l and for use on instruments whose bodies i are not symmetrical or regular. The lengthening or shortening of ie bridge Zi in its entirety adapts the bridge 22 for application to instruments of different widths. It is to be understood that with all these adjustments and with the bridge 20 adjusted as required that all parts of the bridge remain clear and spaced from the top member l1 of the instrument except at the feet 25.

The electrical pickup 2l may be of any selected or required kind. In the drawing I have shown an electrical pickup of the general character described and claimed in United States Letters Patent No. 2,089,171, issued to George D. Beauchamp, August l0, 1937. This type of pickup is an electromagnetic device for converting the tone producing vibrations of the strings S into an induced electrical current having all the characteristics of the tone producing vibrations of the strings, this induced current being suitable for amplification and for delivery to a loud speaker. The pickup 2| comprises a pair of opposed permanent magnets 35 of U shape. The magnets 35 lare arranged with their like poles in opposing spaced relation. The lower arms of the magnets 35 are attached to a plate 36 of magnetic material by screws 3l. The pickup further includes a coil 38 embodying an elongate spool 39 of insulating material and a winding 49 of enameled wire of the correct gauge. The screws 3l may serve to attach the spool 39 to the lower arms of the magnets 35. The coil 38 is supported on the lower arms of the magnets 35 to receive an induced current when the reluctance of the magnetic field is varied by vibration of the strings S. The coil 38 is positioned between the north and south poles of the magnets 35 and is arranged with its long axis parallel with the long axis of the magnet assembly. The top of the coil spool 39 is spaced below the upper magnet arms to leave a space for the strings S as will be later described. Pole pieces 4| extend upwardly through the spool 39 and have their lower ends in electrical contact with the lower arms of the magnets 35. The pole pieces 4| are spaced apart longitudinally of the coil 38 `and are located to have their upper ends oppose the strings S. One or more of the pole pieces 4| is in electrical contact or connection with the inner windings 43 of the coil. The pole pieces 4| operate to concentrate the magnetic force in zones through which the respective strings pass and carry the magnetic force into the central eld of the coil 38. When the strings S are vibrated they vary the reluctance of the magnetic field and thus induce an electrical current in the coil 38. This induced current has all the characteristics of the sound producing vibrations of the strings S. Leads 42 from the terminals of the coil winding 40 extend to a volume control C` suitably attached to one of the end bridge sections 23 and leads or conductors may extend from the volume control C to a suitable amplier and speaker unit, not shown. The details of the pickup 2| form no part of the invention except in combination with the other elements of the invention, the pickup being covered by the Beauchamp patent above referred to.

The means 22 supports the pickup 2| in the position above described where the strings S pass between the ends of their 4| relative to the strings S. The raised major portion of the intermediate bridge section 24 has a longitudinal opening or slot 43 and the magnets 35 and coil 33 extend upwardly through this opening 43 with substantial clearance. In this connection it sho-uld be observed that it is preferred to construct all parts of the bridge 23 of non-magnetic material so that the bridge does not interfere with the magnetic eld of the pickup 2|. The plate 3B is spaced below the intermediate bridge section 24 and is spaced above and entirely clear of the top member Il of the instrument body I9. The means for adjustably mounting the pickup 2| on the bridge 2G includes studs 44 projecting upwardly from the opposite ends of the plate 36. The studs 44 may be in the form of screws whose heads bear upwardly against the under side of the plate 33. Nuts 45 are threaded on the studs 44 to clamp against the top of the plate 36 and thus nx the studs to the plate. The studs 44 pass upwardly through openings 46 in the raised major portion of the intermediate bridge section 24, the openings being adjacent the opposite ends of the elongate opening 43. Nuts 41 are threaded on respective pole piecesv i the upper ends of the studs 44 and washers 48 are provided under the nuts to bear on the top of the section 24. It will be seen that the studs 44 suspend the pickup 2| from the bridge section 24 through the medium of the nuts 4l. By threading or adjusting the nuts 41 either end of the pickup 2| may be adjusted up or down with respect to the series of strings S or the nuts may be manipulated to bodily adjust the entire pickup 2| up or down. Springs 59 surround the studs 44 and are arranged under compression between the under side of the bridge section 24 and the plate 35. The springs 5|) nrmly hold the pickup 2| in the adjusted position and resist unthreading or loosening of the nuts 47.

Fig. 5 of the drawing illustrates a means for removably securing the bridge 23 to a musical instrument body without the necessity of making screw holes or the like in the instrument. In this structure the feet of the bridge 20 carry spaced depending screws or threaded stems 5|. The stems 5| are xed to the feet 25. Lower plates 52, corresponding to and opposing the feet 25, are provided to cooperate with the under side of the instrument body I9. that is, to engage upwardly against the lower body member I8. Studs or threaded stems 53 are fixed to the plates 52 yand extend upwardly in longitudinal alignment with the stems 5|. The stems 5| and 53 are provided with oppositely pitched threads, that is, the stems 5| may have right hand threads, while the stems 53 may have left hand threads. Elongate nuts or sleeves 54 have threaded engagement with the aligned stems 5! and 53. The sleeves 54 are formed for ready turning or rotation, for example, they may have transverse openings 55 for receiving a turning tool or pin. It will be seen that by rotation of the sleeves 54 that the plates 52 may be moved up or down with respect to the feet 25 to x the bridge 20 to the instrument body I3 or to release the bridge for removal. Pads 56 of felt, rubber, or the like, are provided on the feet 25 and plates 52 to engage the upper and lower body members I1 and I8.

It is to be understood that both ends of the bridge 20 may be provided with the structure illustrated in Fig. 5. When the bridge is arranged in the selected position the clamp means is operated to cause its pads 56 to tightly grip the upper and lower body members Il and i3. The sleeves 54 are readily rotated to tightly clamp the feet 25 and the plates 52 against the instrument and to release the feet and plates. The structure of Fig. 5 constitutes a simple effective means for readily securing the bridge 2|) to an instrument body without the necessity of providing holes in the instrument and without mari-ing the instrument in any way and the clamp means is readily loosened to permit detachment of the bridge 20 from the instrument.

It is believed that the utility and practicability of the structure provided by this invention will be readily apparent from the foregoing detailed description. Referring to the forni of structure illustrated in Figs. l to 4, inclusive, the bridge 20 is iirst arranged in the selected position where it extends across the top of the instrument body i3. If necessary, one or both of the screws 32 are loosened to permit adjustment of the bridge. With both screws 32 loosened the bridge may be extended or contracted to bring its feet 25 a the non-vibratile substantially rigid margins of the body member I1. The screws 25 may be employed to secure the feet 25 in the selected positions. It is to be understood that where the instrument is not symmetrical that the bridge 20 may be extended or shortened at one end only to bring the feet 25 to the correct positions. Following the attachment of the bridge 25 to the instrument by means of the screws 26 the intermediate bridge section 24 may be adjusted to centralise the pickup 2| with respect to the strings S. This adjustment of the intermediate section 24 makes it possible to bring the upper ends of the pole pieces 4I directly under their respective strings S. When this adjustment has been made the screws 32 may be tightened. The nuts 4l may be employed at any time to vertically adjust the pickup 2l or to tilt the pickup from either end. These adjustments vary the spacing of the pole pieces 4| from their respective strings S and thus vary to some extent the action of the pickup.

When the bridge embodies the construction illustrated in Fig. 5 the invention is employed as above described except that the sleeves 54 are manipulated to clamp the feet 25 and the plates 52 against the top and bottom members I1 and I8 of the instrument body IIJ to secure the ends of the bridge to the instrument.

The present invention provides simple yet very effective means for adjustably mounting a pickup on the vibratile body of a musical instrument without dampening, deadening or in any way affecting the resonance or tonal qualities of the instrument. This permits the employment of electrical pickups on stringed musical instruments of standard or regular construction and on instruments which are highly prized by their owners by reason of their age, tonal qualities, etc.

Having described typical preferred forms and applications of my invention I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

l. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across the top of the body, said means comprising a bridge extending across the top of the body in spaced relation thereto and bearing on the body at the opposite margins of the body only so that it does not interfere with the resonance of the top of the body, and means for supporting the pickup on the bridge in spaced relation to the body and in operative relation to the strings.

2. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across the top of the body, said means comprising a bridge secured to the margin only ci the body and extending inwardly therefrom in spaced relation to the top of the body so that it does not interfere with the resonance of the top of the body, and means securing the pickup to the bridge for vertical adjustment and to be in spaced relation to the body in a position where it is in the operative relation to the strings.

3. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across the top of the body, said means comprising a bridge having downturned feed on its opposite ends for bearing on the opposite marginal portions of the body, the bridge being adapted to extend across the top of the body in spaced relation thereto and engaging the body through said feet only so that it does not interfere with the resonance of the top of the body, and means for securing the pickup to the bridge to be clear of the top of the body and to be in operative relation to the strings.

4. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across the top of ,the body, said means comprising a bridge bowed upwardly and inwardly from its opposite ends to be clear of and spaced from the body at all points except at its ends when arranged across the top of the body,

means for securing the ends of the bridge to the opposite marginal parts of the body, the bridge being entirely free of and unattached to the body except at said opposite marginal parts so that it does not interfere with the resonance of the top of the body, and means for securing the pickup to the bridge where it is clear of the body and in operative relation to the strings.

5. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across the top of the body, said means comprising a bridge extending across the top of the body in spaced relation theerto and bearing on the body at its opposite margins only so that it does not aiect the resonance of the top of the body, the bridge comprising relatively shiftable sections whereby it is extensible and contractible, and means for supporting the pickup on the bridge in spaced relation to `the body and in operative relation to the strings.

6. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across the top of the body, said means comprising a bridge extending across ,the top of the body in spaced relation thereto and bearing on the body at its opposite margins only so that it does not interfere with the resonance oi the top of the body, the bridge comprising end sections, and an intermediate section shiftably connected with the end sections to provide for adjustment in the length of the bridge and .to provide for adjustment of the intermediate section in a direction transverse of the strings, and means for securing the pickup to the intermediate section.

'7. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across the top of the body, said means comprising a bridge extending across the top of the body in spaced relation thereto and bearing on the body at its opposite margins only so that it does not interfere with the resonance of the body, the bridge comprising two end sections, an intermediate section, and means for shiftably connecting the intermediate section with the end sections to provide for adjustment in the length of the bridge and to provide for adjustment of the intermediate section in a direction transverse of the strings, and means mounting the pickup on the intermediate section for vertical adjustment.

8. Means for supporting a pickup on a musical instrument having a resonant body and strings extending across .the top of the body, said means comprising a bridge extending across the top oi the body in spaced relation thereto, means for detachably securing the opposite ends of the bridge to the opposite edge portions of the body, the bridge being secured to only the opposite edge portions of the body so that it does not interfere with the resonance of the body, and means for securing the pickup to the bridge to be in operative relation to `the strings and to be clear of the body.

the body, the bridge being entirely clear of the body and the clamp means engaging the top of resonance of the body is unaffected and means for securing the pickup to the bridge to be operative relation to the strings and to be clear of the body.

PAUL M. BARTH. 

